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Friday, 15 June 2012

The National Weight Control Registry: the gold standard in bullcrap (Part 1)

Whenever anybody talks about the
futility of trying to lose weight, somebody like That Awful Woman (TAW), who I
won’t give more publicity to by naming, will throw the National Weight Control
Registry (NWCR) in their face. See, it IS possible to lose weight and keep it
off. This is the proof. You’re obviously just not trying hard enough. But as TAW seems to get all her science from the daily news, she could be forgiven for buying into this myth - it has been carefully crafted to make us believe.

Despite reams and reams of evidence
(like this and this and this) showing that NO method of
weight loss leads to long-term maintenance, the NWCR continues to be held up like a
beacon of virtue, giving hope to all of us failed dieters that lifetime change
IS possible. Given the smug condescension with which finger-wagging 'well-wishers', who are apparently just concerned about our health, use the NWCR to belittle and castigate us poor greedy lazy fat people, it is
worth looking a bit closer at just what is being touted as evidence of successful
dieting. How are these people getting it right when everyone else is failing so
miserably?

Well that’s an interesting
question. In fact, that’s the very reason the NWCR was set up in the first
place. Back in the early 90s, researchers from Brown, Colorado and Pittsburgh
universities decided to gather together a database of people who had
successfully lost weight and kept it off. The idea was to study these people
and find out what their secret was. Not a bad idea, really, particularly since
back then we didn’t know as much as we do now about how damaging dieting actually is to your health.

The problems started soon after
when they couldn’t actually find any. Well, that’s a bit unfair. They found a
few. In a country where over 70 million people are thought to be dieting at any
one time, they did managed to attract a few hundred who self-reported that they
had lost the required minimum of 30 pounds, and kept it off for at least a
year. The first major publication from the NWCR team was
based on 784 enrolees who met these criteria.
784. The paper was an analysis of what these people were doing that had helped
them to qualify for the registry in the first place. In fact, some had far
exceeded the minimum criteria. Average weight loss was 30 kg (66 lbs), and
average maintenance was 5 years. It is these particular numbers that are most often
bandied about as proof of successful dieting. So let’s look at them a little
more closely.

First, that minimum 30 lb weight
loss is defined as a weight below their lifetime
maximum. So if you lost 100 lbs from your lifetime max, and regained 70
lbs, you’d still qualify. Even if you’d done it numerous times before: 91% had
previous ‘failed’ weight loss attempts. The ‘average’ amount of weight lost
prior to their current success was 565 lbs. And there was a wide range here,
with some losing over 1000 lbs before successfully managing to keep off their
current minimum of 30. No information on how long previous weight loss
‘successes’ had been maintained. But enough with the cynicism. What were they
doing this time that was different?

Well, 92% were still monitoring
their food intake – counting calories, fat grams and so on. The vast majority
maintained a low calorie diet, through whatever means. 95% of men were getting
between 1100 and 2300 calories, and for women it was between about 800 and 1800
calories a day. The average was 1700 for men and 1300 for women. About half
admitted spending more time and energy thinking about food and weight than they
did before. They also definitely
got a lot more exercise, on average, 2830 calories per week, or roughly
equivalent to walking 28 miles. Again, the range was big, with some doing up to
double this. Most continued to
monitor their weight regularly, with 38% continuing to weigh daily, and 7%
reporting more than once a day. Now I don’t know about you, but if somebody
with a ‘normal’ BMI told me they were thinking about their food and weight a
lot of the time, eating just 1500 calories, monitoring every bite of food that
went into their mouths, walking over 4 miles and weighing themselves at least
once a day, I’d be a bit worried about them.

So that’s how the just under 800
success stories qualified for the NWCR. Even ignoring the well-documented harmful effects of weight cycling (yo-yo dieting), and the somewhat
dubious ‘health’ behaviours used to maintain their current weight, let’s just
assume that this time really was different. Tune in next time for the
not-entirely-surprising results of follow-up studies.